Generally, an electric vehicle is developed in order to prevent environmental contamination, which is presently getting worse, and replace limited fluidic energy with a new energy source and drives a motor by a power of a battery to secure traversability at a predetermined speed or higher.
When a driver operates an accelerator pedal, in the electric vehicle, a controller controls a gate frequency of an inverter depending on an amount of manipulated accelerator pedal to control DC power of the battery in a pulse width modulation (PWM) manner. Accordingly, a predetermined amount of current is supplied to a motor and a predetermined torque is generated in accordance with the supplied current amount to rotate the motor, thereby driving the electric vehicle.
Since a secondary battery with a limited capacity is used for a battery of the electric vehicle, the charged power is consumed when the electric vehicle drives for a predetermined time.
When the battery of the electric vehicle is consumed, the driver charges the battery at home or in a charging station such as a gas station provided with a charging device. In this case, the battery of the electric vehicle is charged by being applied with external AC power and converting the applied external AC power into DC power. That is, since the motor of the electric vehicle needs to be driven by a voltage that is charged within the battery, the electric vehicle uses a large quantity of chargeable battery and includes a battery charging device to charge the large quantity of chargeable battery.
In the meantime, a hybrid electric vehicle or a HEV has an electrical driving train and a gasoline or another type of internal combustion engine. An electric motor is solely configured by a battery pack or combined with an internal combustion engine to generate energy and drives the vehicle in accordance with the generated energy.
One problem of the HEVs which are currently massively produced is that a maximum electric potential of a hybrid driving system is not considered by a limited amount of an on-board electric energy storage. Such a problem is handled as increase of an energy storing capacity of a vehicle to use more power instead of the gasoline, which will be implemented in accordance with a technical improvement of a battery or other types of storing systems. An energy storing system with a high capacity may charge an offset from an external power source and reduce consumption of oil fuel, in other words, alleviate the necessity of an oil fuel engine. Such a configuration is known as a plug in hybrid electric vehicle or a PHEV.
It is considered that even though the PHEV has a battery with a large storing capacity to store electric energy, the stored energy is used only to move the vehicle. When the vehicle is not moved, the battery system does not run (an idle state) and is not utilized. It is recognized that the stored electric energy of the PHEV is used to supply electrical energy when the power is supplied and a demand of a power system is in a peak state and such a concept is referred to as a vehicle to grid or a V2G.
Hereinafter, a power converting apparatus of an electric vehicle according to the related art will be described with reference to FIG. 1.
FIG. 1 is a view illustrating a circuit configuration of a power converting apparatus of an electric vehicle according to the related art.
As illustrated in FIG. 1, a power converting apparatus of an electric vehicle includes a first rectifier 10, a boost converter 11, a low voltage converter 12, a transformer 13, a second rectifier 14, a battery 15, an inverter 16, a motor 17, a mode selector 18, and a controller 19.
With this configuration, a charging mode operation of the battery 15 and a driving mode operation of the motor 17 will be described, respectively.
First, when a charging mode is selected by the mode selector 18, the first rectifier 10 full-wave rectifies a supplied AC voltage to output the AC voltage to the boost converter 11. Here, the input AC voltage is a single phase voltage and the first rectifier 10 full-wave rectifies the input single-phase voltage.
The boost converter 11 converts the full-wave rectified voltage which is output from the first rectifier 11 into a DC voltage to output the converted DC voltage to the low voltage converter 12.
The low voltage converter 12 is a DC-DC converter which includes a plurality of switching elements S1 to S4 and the plurality of switching elements is repeatedly turned on and turned off in accordance with a switching control signal which is provided from the controller 19 in accordance with the selected charging mode to generate the DC voltage.
The DC voltage generated as described above is converted into a predetermined voltage through the transformer 13, rectified by the second rectifier 14, and then charged into the battery 15.
In summary, when a charging mode is selected by the mode selector 18, the voltage from an AC power source (110 V or 220 V) which is a commercially used power source is full-wave rectified by the first rectifier 10 and an output voltage is converted through the boost converter 11, the low voltage converter 12, the transformer 13, and the second rectifier 14 in accordance with a battery charging voltage to charge the battery 15.
In the meantime, when the driving mode is selected by the mode selector 18, the controller 19 supplies a switching control signal to the inverter 16 to turn on the plurality of switching elements S1 to S6, thereby converting the DC output power of the battery 15 into power of a three-phase voltage suitable for the motor 17. Therefore, the converted three-phase power is supplied to the motor 17 to drive the motor 17. Here, the inverter 16 is a 70 KW or higher system and is configured with a three-phase structure.
When the power converting apparatus of the electric vehicle according to the related art as described above is configured with a three-phase structure, six or more high specification rectifier diodes are used as a rectifier diode at a secondary side of the OBC, so that cost may be increased.
In the meantime, in the power converting apparatus of the electric vehicle according to the related art, the OBC system and an inverter system for driving the motor are configured by a package having separate housings, so that a volume is increased and a weight is also increased.